Telephone-circuit.



Patented Nov.- [3, I900. I. H. FARNHAM &. G. W. DAVIS.

TELEPHONE CIRCUIT.

(Appiication filed -May 11, 1900.1

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Patented Nov. [3, I900. l. H. FARNHAM'& G. W. DAVIS.

TELEPHONE CIRCUIT.

(Application filed May 11, 1900.1

2 Sheets-Sheet 2.

(No Model.)

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' NiTED STATES PATENT OFFICE.

ISAIAH H. FARNHAM, OF YVELLESLEY, AND GEORGE W. DAVIS, OF REVERE,MASSACHUSETTS, ASSIGNORS TO THE NEIV ENGLAND TELEPHONE AND TELEGRAPHCOMPANY, OF BOSTON, MASSACHUSETTS.

TELEPHONE-CIRCUIT.-

SPECIFICATION forming part of Letters Patent No. 661,714, dated November13, 1900.

Application filed May 11, 1900. Serial No. 16,306." (No model.)

To all whom it may concern:

Be it known that we, ISAIAH H. FARNHAM, residing at Wellesley, in thecounty of Norfolk, and GEORGE W. DAVIS, residing at Re: Vere, in thecounty of Suffolk, State of Massachusetts, have inventedcertainlmprovements in Telephone-Circuits, of which'the following is aspecification.

In the operation of street and other railways it frequently becomesdesirable for the conductor of a car or of a train of cars to eifeclcommunication with a central station in order to report thereto anytrouble that may have occurred to the railway equipment or for any otherreasons which require immediate help or attention.

The object of the present invention is to provide means whereby theconductor of a car may connect himself telephonic-ally with a centralstation, and to this end we provide a circuit whose conductors arestrung upon the telegraph-poles along the route of the track, in casethe invention is applied to steam-railways provided with such poles, andif the application is to an electric-car railway the conductors arecarried upon the supports which carry the trolley or feed wires. Theseconductors are open at one end and at the other end enter the centralstation and are closed there through a'generator of electricity and arelay controlling a bell or signal, which circuit is adapted when it isclosed at any point away from the central station to ring a bell ordisplay a visual signal, there being an attendants or operatorstelephone in a normally open shunt around the generator and signal.

At suitable intervals in the circuit normally open branch terminalconductors are 40 brdhght down from each of the line conductors toswitch-boxes, preferably of iron, secured to the sides of the poles.Each switch box is provided with a door or cover and with suitablespring-socket contacts for the reception of plug-connectors. Thebranching conductors are protected in iron pipes, which extend from theboxes ..to a proper height above the same. To enable the conductor of acar or train to communicate with the central station, we provide atransmitting and a receiving telephone and a flexible extensibleplug-connector, all adapted to be inclosed and protected within aportable box or case, the telephone -transmitter being preferablysecured to the back of the box, the

receiving-telephone being provided with a support, and space being madefor the said connector, the box itself having a suitable handle by whichthe whole outfit may be readily carried about and supported upon a polewhen in use. When not in use, the portable telephone set may be placedin a locker of the car.

When the conductor wishes to communicate with the central station, theportable set is carried to a pole upon which is secured a switch-box,and the handle thereof is hung over the switch-box, the door opened, andthe plug-connector taken outand inserted into the spring-sockets of theswitch-box and the telephone-receiver removed from its support. Theinsertion of the plug-connector into the said sockets closes andcompletes the circuit through the generator and the relay controllingthe bell or signal at the central station, and thereupon the bell ringsor-a signal is displayed, and when in response thereto the attendantremoves the telephone from its hook-switch to answer the call the switchoperates to include the central-station telephones in the line-circuitand at the same time to open the bell or signal circuit.

The invention relates to the circuits shown anddescribed and to thespecific mechanical and electrical appliances used in connectiontherewith.

In the drawings which illustrate the invention, Figure l is aperspective view of an electric trolley-railway. Fig. 2 is a detachedportion of a conductor-supporting pole, showing the location thereon ofa switch-box and the suspension thereto of a portable telephone outfit.Fig. 3 is an enlarged portion of the switch-box with its door or coverremoved. Fig. 4 is an enlarged view of the portable telephone outfit,showing the door open and the plug-connector removed. Fig. 5 is 21diagram of the circuits embodied in the invention, illustrating theconnection of three railway-circuits with a central station; and Figs.

6 and 7 are modifications of the switch-box.

Referring to the drawings, a a represent the conductor-so pporting polesof an electric trol Icy-railway. t

Z) b are projecting-arms sustaining the trolley-wire c.

d d are cross-arms having on each end insulators e e, to which areattached the conductors ff which constitute the circuit F,

extending to the central station L. At, suitable intervals branchconductors g g extend from the respective conductors ff and pass down aprotecting-pipe h, whose upper end is covered by any suitable cap 41.

lower side of the box A. The block tis fas- The tened to the box A bythe screws to u. holes inthe floor of the box are made larger indiameter than those in the blocku to prevent electrical contact with theconnectingplugs.

13 represents the box which contains the portable telephone outfit,provided with the door D on the front side, hinged to the box andadapted to be secured when closed by the v hasp and button 8 and 9, andZ0 is a handle, preferably Hat and flexible, secured at each end to theopposite sides of the box. Within the box and to its back is secured atelephonetransmitter M, and the telephone-receiver T is adapted to besupported therein upon the cleats 5 and 6, and its terminals areconnected by the flexible cord P to the screw-posts 3 and 4. p

C is a double plug-connector consisting of an insulating-handle in whichare inserted the metal plugs or terminals 12 and w of differentdiameters, which are connected to the insulated conductors g and 9 whichconstitute the flexible cord E and are joined to the opposite poles-ofthe battery H, the electro-,

magnet of the signal-controlling relay I being shown in circuit with thelatter conductor. A

Wire 14 connects the conductor f with the.

foot of the relay-armature 12, whose free end is opposite a terminal 13of the bell J, whose opposite side is connected by wire 11 with theresting-contact 21 of the hook-switch 10, and

The lowerend of the pipe is screwed into the upper side of wire fconnects the point 20 with the hookswitch. The telephones are in serieswith one another by means of the wire 8, which connects one side of thereceiver T with point 7 on conductor f It Will be readily understoodthat an annunciator or other visual signal may be substituted for thebell.

The operation of the invention is quite apparent from what has beensaid; but a brief description will perhaps be required When for anycause the conductor of a car wishes to communicate with the centralstation, the box B is suspended from the switch-box A by passing itsstrap handle over the latter, as shown in Fig. 2, the plug-connector Cremoved from t-hebox, and its terminals inserted into theswitch-sockets-the plug '0 into the hole 'v and the plug 20 into thehole w-and as the connector is pressed in the springs s and 8 are forcedagainst the respective springterminals 19 and p so that the circuit iscontinued from the branches 9, spring-terminals p, springs s, to therespective jplugs, as will be easily understood. The springs s s bytheir bent ends furnish a protection to the circuit springs, and if anyforeign plug or wire is mischievously inserted no connection is madewith the connectors 13, and a further protection is. provided in makingthe plugs and their sockets of different diameters, and

the battery-current is thus always passed through the receiverin thesame direction, preventing the demagnetizing of the receivermagnet. Whenthe plug-connector O is thus inserted, the circuit is closed therebythrough the central-station battery H, the relay I operates in awell-known manner, and the bell rings or a visual signal is displayed.When the telephone T is removed, the switch 10 in rising closes withcontact 9 and opens the signal-circuit and includes the telephones inthe shunt-circuit. Current from battery H then circulates throughout thecircuit F, and when the transmitters are used the current is varied in awell-known manner.

One op'erators telephone set may be made available fora plurality ofrailway routes, as indicated in Fig. 5, and there will be no disturbanceshould a call bereceived from a box on a second route while conversationis taking place between a boxon any route and the central station, asthe operator can easily take care of both. v

Fig. 6 represents a modification of the switch-box, in which thebranches 9 and g are connected to spring-terminals s and 8 secured tothe insulating-block M, and C is a single plug provided with twocontact-surfaces 0 and 7113, which register with the springs s and 8respectively. The plug 0 is adapted to be passed through a hole in thefloor of the box large enough to prevent the plug from coming intocontact with its sides. Fig. 7 is another modification of the switchbox,in which'a double plug is used. In this case the door is hinged to thecase and is locked thereto when closed, and to insert the plug the dooris opened. There are some advantages in this construction, as noapertures are made in the walls of the box.

It is within the spirit of our invention to use a portable transmitterand receiver, both of which are secured to a common bar or support of awell-known construction, and the instruments will be connected by aflexible cord with the plug-connector.

We claim as our invention- 1. A telephonic circuit composed of twoconductors open at one end and provided with a series of branchesextending from the conductors to normally open terminal switchesinclosed in a series of boxes; the other end of said circuit beingclosed through an electric generator; a branch from one of saidconductors including telephones normally open at the hook-switch; asignal-circuit controller having its windings in one of said conductors,a signal adapted to be operated by said controller and to be included inparallel with said generator, and adapted to be inoperative by the saidhook-switch; with a portable telephonic outfit or set, inclosed in abox, consisting of a telephone-transmitter, a receiver, and aplug-connector, united in series by con ducting-wires, as set forth.

2. A telephonic circuit composed of two conductors open at one end andprovided with a series of branch extensions from the conductors tonormally open terminal switches inclosed in a series of boxes; the otherend of the circuit being closed through an electric generator; a branchfrom one of the conductors includingtransmitting and receivingtelephones normally open at the hook-switch; a signal-circuit controllerhaving its windings in one of the conductors, asignal in a circuitparallel with the generator open at the controller and normally closedby the hookswitch; with a portable telephonic set inclosed in a boxconsisting of a telephonetransmitter, a receiver and a double plug-connector united in series by conducting-wires, as set forth.

3. A system of telephonic intercom m unication composed of a pluralityof metallic circuits each comprising two conductors open at their outerends and provided with a series of branch extensions from theirconductors to normally open terminal switches inclosed in a series ofboxes; the inner ends of the circuit-conductors being combined andclosed through an electric generator at a central station; a branch fromone side of the combined circuit including transmitting and receivingtelephones normally open at the hook-switch; a signal-circuit controllerhaving its windings in one side of the combined circuit, a signal in acircuit parallel with the generator open at the controller and normallyclosed by the hook-switch; with a portable set or sets, inclosed in abox consisting of a telephonetransmitter, a receiver and aplug-connector, united in series by conducting-wires, as set forth.

4. A system of telephonic intercommunication comprised of a metalliccircuit open at one end and closed through a battery and the windings ofa signalcircuit-controlling relay at a central station; a signal devicein a derived circuit around said battery normally open at said relay andnormally closed at and by the telephone-hook switch; transmitting andreceiving telephones in a normally open derived circuit around saidbattery; the circuit-conductors being secured to a series of poles; aseries of branches extending from the conductors to normally openterminal switches inclosed in a series of boxes secured to said poles;with a portable telephonic outfit or set inclosed in a box consisting ofa fixed telephone-transmitter, a movable telephonereceiver and aplug-connector, united in series by connecting-wires, as set forth.

5. A switch-box for the purpose set forth, adapted to be secured to asuitable support, consisting of a metal casing provided with adetachably-secured door or side; a block of insulation secured to a wallof the box supporting two spring-terminals, and two springconnectorswit-h bent ends; a second block of insulation secured to a wall of thebox having holes opposite the said spring-connectors and coinciding withholes in the wall of the box; with a tube extending upward from the boxto the top of which is secured a protectingcap, as set forth.

In testimony whereof we have signed our names to this specification, inthe presence of two subscribing witnesses,this 8th day of May, 1900.

ISAIAH H. FARNHAM.

GEORGE W. DAVIS. Witnesses:

WILLIAM S. WILDER, GEORGE S. MOYNAHAN.

